wiretap/dct3trace.c

   1 /* dct3trace.c
   2  * Routines for reading signalling traces generated by Gammu (www.gammu.org)
   3  * from Nokia DCT3 phones in Netmonitor mode.
   4  *
   5  * gammu --nokiadebug nhm5_587.txt v18-19
   6  *
   7  * Duncan Salerno <duncan.salerno@googlemail.com>
   8  *
   9  * Wiretap Library
  10  * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28 #include "wtap-int.h"
  29 #include "dct3trace.h"
  30 #include "file_wrappers.h"
  31
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35
  36 /*
  37    Example downlink data:
  38
  39 <?xml version="1.0"?>
  40 <dump>
  41 <l1 direction="down" logicalchannel="96" physicalchannel="19" sequence="268116" error="0" timeshift="2992" bsic="22" data="31063F100DD0297A53E1020103C802398E0B2B2B2B2B2B" >
  42 <l2 data="063F100DD0297A53E1020103" rest="C802398E0B2B2B2B2B2B" >
  43 </l2>
  44 </l1>
  45 </dump>
  46
  47    Example uplink data (no raw L1):
  48
  49 <?xml version="1.0"?>
  50 <dump>
  51 <l1 direction="up" logicalchannel="112" >
  52 <l2 type="U" subtype="Unknown" p="0" data="061500400000000000000000000000000000" >
  53 </l2>
  54 </l1>
  55 </dump>
  56
  57  */
  58
  59
  60 /* Magic text to check */
  61 static const char dct3trace_magic_line1[] = "<?xml version=\"1.0\"?>";
  62 static const char dct3trace_magic_line2[] = "<dump>";
  63 static const char dct3trace_magic_record_start[]  = "<l1 ";
  64 static const char dct3trace_magic_record_end[]  = "</l1>";
  65 static const char dct3trace_magic_l2_start[]  = "<l2 ";
  66 #if 0 /* Not used ?? */
  67 static const char dct3trace_magic_l2_end[]  = "</l2>";
  68 #endif
  69 static const char dct3trace_magic_end[]  = "</dump>";
  70
  71 #define MAX_PACKET_LEN 23
  72
  73 static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,
  74         gint64 *data_offset);
  75 static gboolean dct3trace_seek_read(wtap *wth, gint64 seek_off,
  76         struct wtap_pkthdr *phdr, Buffer *buf, int *err, gchar **err_info);
  77
  78 /*
  79  * Following 3 functions taken from gsmdecode-0.7bis, with permission - http://wiki.thc.org/gsm
  80  */
  81
  82 static int
  83 hc2b(unsigned char hex)
  84 {
  85         hex = g_ascii_tolower(hex);
  86         if ((hex >= '0') && (hex <= '9'))
  87                 return hex - '0';
  88         if ((hex >= 'a') && (hex <= 'f'))
  89                 return hex - 'a' + 10;
  90         return -1;
  91 }
  92
  93 static int
  94 hex2bin(guint8 *out, guint8 *out_end, char *in)
  95 {
  96         guint8 *out_start = out;
  97         int is_low = 0;
  98         int c;
  99
 100         while (*in != '\0')
 101         {
 102                 c = hc2b(*(unsigned char *)in);
 103                 if (c < 0)
 104                 {
 105                         in++;
 106                         continue;
 107                 }
 108                 if (out == out_end)
 109                 {
 110                         /* Too much data */
 111                         return -1;
 112                 }
 113                 if (is_low == 0)
 114                 {
 115                         *out = c << 4;
 116                         is_low = 1;
 117                 } else {
 118                         *out |= (c & 0x0f);
 119                         is_low = 0;
 120                         out++;
 121                 }
 122                 in++;
 123         }
 124
 125         return (int)(out - out_start);
 126 }
 127
 128 static int
 129 xml_get_int(int *val, const char *str, const char *pattern)
 130 {
 131         const char *ptr;
 132         char *start, *end;
 133         char buf[32];
 134
 135         ptr = strstr(str, pattern);
 136         if (ptr == NULL)
 137                 return -1;
 138         start = strchr(ptr, '"');
 139         if (start == NULL)
 140                 return -2;
 141         start++;
 142         end = strchr(start, '"');
 143         if (end == NULL)
 144                 return -3;
 145         if (end - start > 31)
 146                 return -4;
 147
 148         memcpy(buf, start, end - start);
 149         buf[end - start] = '\0';
 150         *val = atoi(buf);
 151         return 0;
 152 }
 153
 154
 155 wtap_open_return_val dct3trace_open(wtap *wth, int *err, gchar **err_info)
 156 {
 157         char line1[64], line2[64];
 158
 159         /* Look for Gammu DCT3 trace header */
 160         if (file_gets(line1, sizeof(line1), wth->fh) == NULL ||
 161                 file_gets(line2, sizeof(line2), wth->fh) == NULL)
 162         {
 163                 *err = file_error(wth->fh, err_info);
 164                 if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
 165                         return WTAP_OPEN_ERROR;
 166                 return WTAP_OPEN_NOT_MINE;
 167         }
 168
 169         /* Don't compare line endings */
 170         if( strncmp(dct3trace_magic_line1, line1, strlen(dct3trace_magic_line1)) != 0 ||
 171                 strncmp(dct3trace_magic_line2, line2, strlen(dct3trace_magic_line2)) != 0)
 172         {
 173                 return WTAP_OPEN_NOT_MINE;
 174         }
 175
 176         wth->file_encap = WTAP_ENCAP_GSM_UM;
 177         wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_DCT3TRACE;
 178         wth->snapshot_length = 0; /* not known */
 179         wth->subtype_read = dct3trace_read;
 180         wth->subtype_seek_read = dct3trace_seek_read;
 181         wth->file_tsprec = WTAP_TSPREC_SEC;
 182
 183         return WTAP_OPEN_MINE;
 184 }
 185
 186
 187 static gboolean dct3trace_get_packet(FILE_T fh, struct wtap_pkthdr *phdr,
 188         Buffer *buf, int *err, gchar **err_info)
 189 {
 190         char line[1024];
 191         guint8 databuf[MAX_PACKET_LEN], *bufp;
 192         gboolean have_data = FALSE;
 193         int len = 0;
 194
 195         bufp = &databuf[0];
 196         while (file_gets(line, sizeof(line), fh) != NULL)
 197         {
 198                 if( memcmp(dct3trace_magic_end, line, strlen(dct3trace_magic_end)) == 0 )
 199                 {
 200                         /* Return on end of file </dump> */
 201                         *err = 0;
 202                         return FALSE;
 203                 }
 204                 else if( memcmp(dct3trace_magic_record_end, line, strlen(dct3trace_magic_record_end)) == 0 )
 205                 {
 206                         /* Return on end of record </l1> */
 207                         if( have_data )
 208                         {
 209                                 /* We've got a full packet! */
 210                                 phdr->rec_type = REC_TYPE_PACKET;
 211                                 phdr->presence_flags = 0; /* no time stamp, no separate "on the wire" length */
 212                                 phdr->ts.secs = 0;
 213                                 phdr->ts.nsecs = 0;
 214                                 phdr->caplen = len;
 215                                 phdr->len = len;
 216
 217                                 *err = 0;
 218
 219                                 /* Make sure we have enough room for the packet */
 220                                 ws_buffer_assure_space(buf, phdr->caplen);
 221                                 memcpy( ws_buffer_start_ptr(buf), databuf, phdr->caplen );
 222
 223                                 return TRUE;
 224                         }
 225                         else
 226                         {
 227                                 /* If not got any data return error */
 228                                 *err = WTAP_ERR_BAD_FILE;
 229                                 *err_info = g_strdup_printf("dct3trace: record without data");
 230                                 return FALSE;
 231                         }
 232                 }
 233                 else if( memcmp(dct3trace_magic_record_start, line, strlen(dct3trace_magic_record_start)) == 0 )
 234                 {
 235                         /* Parse L1 header <l1 ...>*/
 236                         int channel, tmp;
 237                         char *ptr;
 238
 239                         phdr->pseudo_header.gsm_um.uplink = !strstr(line, "direction=\"down\"");
 240                         if (xml_get_int(&channel, line, "logicalchannel") != 0)
 241                                 goto baddata;
 242
 243                         /* Parse downlink only fields */
 244                         if( !phdr->pseudo_header.gsm_um.uplink )
 245                         {
 246                                 if (xml_get_int(&tmp, line, "physicalchannel") != 0)
 247                                         goto baddata;
 248                                 phdr->pseudo_header.gsm_um.arfcn = tmp;
 249                                 if (xml_get_int(&tmp, line, "sequence") != 0)
 250                                         goto baddata;
 251                                 phdr->pseudo_header.gsm_um.tdma_frame = tmp;
 252                                 if (xml_get_int(&tmp, line, "bsic") != 0)
 253                                         goto baddata;
 254                                 phdr->pseudo_header.gsm_um.bsic = tmp;
 255                                 if (xml_get_int(&tmp, line, "error") != 0)
 256                                         goto baddata;
 257                                 phdr->pseudo_header.gsm_um.error = tmp;
 258                                 if (xml_get_int(&tmp, line, "timeshift") != 0)
 259                                         goto baddata;
 260                                 phdr->pseudo_header.gsm_um.timeshift = tmp;
 261                         }
 262
 263                         switch( channel )
 264                         {
 265                                 case 128: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_SDCCH; break;
 266                                 case 112: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_SACCH; break;
 267                                 case 176: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_FACCH; break;
 268                                 case 96: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_CCCH; break;
 269                                 case 80: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_BCCH; break;
 270                                 default: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_UNKNOWN; break;
 271                         }
 272
 273                         /* Read data (if have it) into databuf */
 274                         ptr = strstr(line, "data=\"");
 275                         if( ptr )
 276                         {
 277                                 have_data = TRUE; /* If has data... */
 278                                 len = hex2bin(bufp, &databuf[MAX_PACKET_LEN], ptr+6);
 279                                 if (len == -1)
 280                                 {
 281                                         *err = WTAP_ERR_BAD_FILE;
 282                                         *err_info = g_strdup_printf("dct3trace: record length %d too long", phdr->caplen);
 283                                         return FALSE;
 284                                 }
 285                         }
 286                 }
 287                 else if( !have_data && memcmp(dct3trace_magic_l2_start, line, strlen(dct3trace_magic_l2_start)) == 0 )
 288                 {
 289                         /* For uplink packets we might not get the raw L1, so have to recreate it from the L2 */
 290                         /* Parse L2 header if didn't get data from L1 <l2 ...> */
 291                         int data_len;
 292                         char *ptr = strstr(line, "data=\"");
 293
 294                         if( !ptr )
 295                         {
 296                                 continue;
 297                         }
 298
 299                         have_data = TRUE;
 300
 301                         /*
 302                          * We know we have no data already, so we know
 303                          * we have enough room for the header.
 304                          */
 305                         if( phdr->pseudo_header.gsm_um.channel == GSM_UM_CHANNEL_SACCH || phdr->pseudo_header.gsm_um.channel == GSM_UM_CHANNEL_FACCH || phdr->pseudo_header.gsm_um.channel == GSM_UM_CHANNEL_SDCCH )
 306                         {
 307                                 /* Add LAPDm B header */
 308                                 memset(bufp, 0x1, 2);
 309                                 len = 3;
 310                         }
 311                         else
 312                         {
 313                                 /* Add LAPDm Bbis header */
 314                                 len = 1;
 315                         }
 316                         bufp += len;
 317
 318                         data_len = hex2bin(bufp, &databuf[MAX_PACKET_LEN], ptr+6);
 319                         if (data_len == -1)
 320                         {
 321                                 *err = WTAP_ERR_BAD_FILE;
 322                                 *err_info = g_strdup_printf("dct3trace: record length %d too long", phdr->caplen);
 323                                 return FALSE;
 324                         }
 325                         len += data_len;
 326
 327                         /* Add LAPDm length byte */
 328                         *(bufp - 1) = data_len << 2 | 0x1;
 329                 }
 330         }
 331
 332         *err = file_error(fh, err_info);
 333         if (*err == 0)
 334         {
 335                 *err = WTAP_ERR_SHORT_READ;
 336         }
 337         return FALSE;
 338
 339 baddata:
 340         *err = WTAP_ERR_BAD_FILE;
 341         *err_info = g_strdup_printf("dct3trace: record missing mandatory attributes");
 342         return FALSE;
 343 }
 344
 345
 346 /* Find the next packet and parse it; called from wtap_read(). */
 347 static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,
 348     gint64 *data_offset)
 349 {
 350         *data_offset = file_tell(wth->fh);
 351
 352         return dct3trace_get_packet(wth->fh, &wth->phdr, wth->frame_buffer,
 353             err, err_info);
 354 }
 355
 356
 357 /* Used to read packets in random-access fashion */
 358 static gboolean dct3trace_seek_read(wtap *wth, gint64 seek_off,
 359         struct wtap_pkthdr *phdr, Buffer *buf, int *err, gchar **err_info)
 360 {
 361         if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
 362         {
 363                 return FALSE;
 364         }
 365
 366         return dct3trace_get_packet(wth->random_fh, phdr, buf, err, err_info);
 367 }
 368
 369 /*
 370  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 371  *
 372  * Local variables:
 373  * c-basic-offset: 8
 374  * tab-width: 8
 375  * indent-tabs-mode: t
 376  * End:
 377  *
 378  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 379  * :indentSize=8:tabSize=8:noTabs=false:
 380  */